It's kind of incredible for a person to be aware of surveillance capitalism and also store "151 thousand emails" unencrypted on a third party server.

The same emails could be routinely downloaded offline for archiving and removed from possible prying eyes elsewhere.

Personally, I use https://github.com/joeyates/imap-backup to archive all my emails and then only keep them on the remote server for as long as I need to (basically until I read them and respond or download an attachment into https://docs.paperless-ngx.com )